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<a name="1" href="#1">1</a>   <em>/**<em>*</em></em>
<a name="2" href="#2">2</a>   <em> * $Id: DirectServlet.html 12 2009-01-29 12:00:24Z azeckoski $</em>
<a name="3" href="#3">3</a>   <em> * $URL: http://entitybus.googlecode.com/svn/maven/site/entitybus-utils/xref/org/sakaiproject/entitybus/util/servlet/DirectServlet.html $</em>
<a name="4" href="#4">4</a>   <em> * Example.java - entity-broker - 31 May 2007 7:01:11 PM - azeckoski</em>
<a name="5" href="#5">5</a>   <em> **************************************************************************</em>
<a name="6" href="#6">6</a>   <em> * Copyright (c) 2007, 2008 Sakai Foundation</em>
<a name="7" href="#7">7</a>   <em> *</em>
<a name="8" href="#8">8</a>   <em> * Licensed under the Educational Community License, Version 2.0 (the "License");</em>
<a name="9" href="#9">9</a>   <em> * you may not use this file except in compliance with the License.</em>
<a name="10" href="#10">10</a>  <em> * You may obtain a copy of the License at</em>
<a name="11" href="#11">11</a>  <em> *</em>
<a name="12" href="#12">12</a>  <em> *       <a href="http://www.osedu.org/licenses/ECL-2.0" target="alexandria_uri">http://www.osedu.org/licenses/ECL-2.0</a></em>
<a name="13" href="#13">13</a>  <em> *</em>
<a name="14" href="#14">14</a>  <em> * Unless required by applicable law or agreed to in writing, software</em>
<a name="15" href="#15">15</a>  <em> * distributed under the License is distributed on an "AS IS" BASIS,</em>
<a name="16" href="#16">16</a>  <em> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</em>
<a name="17" href="#17">17</a>  <em> * See the License for the specific language governing permissions and</em>
<a name="18" href="#18">18</a>  <em> * limitations under the License.</em>
<a name="19" href="#19">19</a>  <em> */</em>
<a name="20" href="#20">20</a>  
<a name="21" href="#21">21</a>  <strong>package</strong> org.sakaiproject.entitybus.util.servlet;
<a name="22" href="#22">22</a>  
<a name="23" href="#23">23</a>  <strong>import</strong> java.io.IOException;
<a name="24" href="#24">24</a>  
<a name="25" href="#25">25</a>  <strong>import</strong> javax.servlet.ServletException;
<a name="26" href="#26">26</a>  <strong>import</strong> javax.servlet.http.HttpServlet;
<a name="27" href="#27">27</a>  <strong>import</strong> javax.servlet.http.HttpServletRequest;
<a name="28" href="#28">28</a>  <strong>import</strong> javax.servlet.http.HttpServletResponse;
<a name="29" href="#29">29</a>  
<a name="30" href="#30">30</a>  <strong>import</strong> org.apache.commons.logging.Log;
<a name="31" href="#31">31</a>  <strong>import</strong> org.apache.commons.logging.LogFactory;
<a name="32" href="#32">32</a>  
<a name="33" href="#33">33</a>  <strong>import</strong> org.sakaiproject.entitybus.entityprovider.extension.Formats;
<a name="34" href="#34">34</a>  <strong>import</strong> org.sakaiproject.entitybus.exception.EntityException;
<a name="35" href="#35">35</a>  <strong>import</strong> org.sakaiproject.entitybus.providers.EntityRequestHandler;
<a name="36" href="#36">36</a>  
<a name="37" href="#37">37</a>  <em>/**<em>*</em></em>
<a name="38" href="#38">38</a>  <em> * This is the core abstract DirectServlet class which is meant to extended,</em>
<a name="39" href="#39">39</a>  <em> * extend this to plugin whatever system you have for initiating/retrieving the EB services</em>
<a name="40" href="#40">40</a>  <em> * and for handling logins &lt;br/></em>
<a name="41" href="#41">41</a>  <em> * &lt;br/></em>
<a name="42" href="#42">42</a>  <em> * Direct servlet allows unfettered access to entity URLs within the EB system, it also can handle</em>
<a name="43" href="#43">43</a>  <em> * authentication (login) if required (without breaking an entity URL)</em>
<a name="44" href="#44">44</a>  <em> * </em>
<a name="45" href="#45">45</a>  <em> * @author Aaron Zeckoski (aaron@caret.cam.ac.uk)</em>
<a name="46" href="#46">46</a>  <em> */</em>
<a name="47" href="#47">47</a>  <strong>public</strong> <strong>abstract</strong> <strong>class</strong> <a href="../../../../../org/sakaiproject/entitybus/util/servlet/DirectServlet.html">DirectServlet</a> <strong>extends</strong> HttpServlet {
<a name="48" href="#48">48</a>  
<a name="49" href="#49">49</a>      <strong>protected</strong> <strong>static</strong> <strong>final</strong> Log log = LogFactory.getLog(DirectServlet.<strong>class</strong>);
<a name="50" href="#50">50</a>  
<a name="51" href="#51">51</a>      <strong>protected</strong> <strong>transient</strong> EntityRequestHandler entityRequestHandler;
<a name="52" href="#52">52</a>      <strong>public</strong> <strong>void</strong> setEntityRequestHandler(EntityRequestHandler entityRequestHandler) {
<a name="53" href="#53">53</a>          <strong>this</strong>.entityRequestHandler = entityRequestHandler;
<a name="54" href="#54">54</a>      }
<a name="55" href="#55">55</a>  
<a name="56" href="#56">56</a>  
<a name="57" href="#57">57</a>      <em>/**<em>*</em></em>
<a name="58" href="#58">58</a>  <em>     * This runs on servlet initialization (it is the first thing to run)</em>
<a name="59" href="#59">59</a>  <em>     * This must be implemented to provide the entity request handler itself &lt;br/></em>
<a name="60" href="#60">60</a>  <em>     * This needs to at least load up the entityRequestHandler service (from the entity broker core)</em>
<a name="61" href="#61">61</a>  <em>     * in order for things to work, if that service is not loaded then nothing will work,</em>
<a name="62" href="#62">62</a>  <em>     * this can be done using a service manager of some kind or by loading it up manually,</em>
<a name="63" href="#63">63</a>  <em>     * the default is to create and load it manually by calling this method with the service &lt;br/></em>
<a name="64" href="#64">64</a>  <em>     * Can also call the servlet constructor to set this value but that is really for testing</em>
<a name="65" href="#65">65</a>  <em>     * </em>
<a name="66" href="#66">66</a>  <em>     * @return the entity request handler service object</em>
<a name="67" href="#67">67</a>  <em>     */</em>
<a name="68" href="#68">68</a>      <strong>protected</strong> <strong>abstract</strong> EntityRequestHandler initializeEntityRequestHandler();
<a name="69" href="#69">69</a>  
<a name="70" href="#70">70</a>      <em>/**<em>*</em></em>
<a name="71" href="#71">71</a>  <em>     * This should return the userId for the currently logged in user if there is one,</em>
<a name="72" href="#72">72</a>  <em>     * if not user is logged in then this should return null</em>
<a name="73" href="#73">73</a>  <em>     * @return the user identifier for the currently logged in user</em>
<a name="74" href="#74">74</a>  <em>     */</em>
<a name="75" href="#75">75</a>      <strong>protected</strong> <strong>abstract</strong> String getCurrentLoggedInUserId();
<a name="76" href="#76">76</a>  
<a name="77" href="#77">77</a>      <em>/**<em>*</em></em>
<a name="78" href="#78">78</a>  <em>     * Handle the user authentication (login) in a system specific way,</em>
<a name="79" href="#79">79</a>  <em>     * by default this will simply fail as entity-broker has no way to authenticate</em>
<a name="80" href="#80">80</a>  <em>     * </em>
<a name="81" href="#81">81</a>  <em>     * @param req the http request (from the client)</em>
<a name="82" href="#82">82</a>  <em>     * @param res the http response (back to the client)</em>
<a name="83" href="#83">83</a>  <em>     * @param path current request path, set ONLY if we want this to be where to redirect the user after a successful login</em>
<a name="84" href="#84">84</a>  <em>     */</em>
<a name="85" href="#85">85</a>      <strong>protected</strong> <strong>abstract</strong> <strong>void</strong> handleUserLogin(HttpServletRequest req, HttpServletResponse res, String path);
<a name="86" href="#86">86</a>  
<a name="87" href="#87">87</a>  
<a name="88" href="#88">88</a>      <em>/**<em>*</em></em>
<a name="89" href="#89">89</a>  <em>     * Default constructor</em>
<a name="90" href="#90">90</a>  <em>     */</em>
<a name="91" href="#91">91</a>      <strong>public</strong> <a href="../../../../../org/sakaiproject/entitybus/util/servlet/DirectServlet.html">DirectServlet</a>() {
<a name="92" href="#92">92</a>      }
<a name="93" href="#93">93</a>  
<a name="94" href="#94">94</a>      <em>/**<em>*</em></em>
<a name="95" href="#95">95</a>  <em>     * Allow the request handler to be set on this servlet,</em>
<a name="96" href="#96">96</a>  <em>     * probably best to only use this for testing</em>
<a name="97" href="#97">97</a>  <em>     * @param entityRequestHandler the entity request handler service object</em>
<a name="98" href="#98">98</a>  <em>     */</em>
<a name="99" href="#99">99</a>      <strong>public</strong> <a href="../../../../../org/sakaiproject/entitybus/util/servlet/DirectServlet.html">DirectServlet</a>(EntityRequestHandler entityRequestHandler) {
<a name="100" href="#100">100</a>         <strong>this</strong>.entityRequestHandler = entityRequestHandler;
<a name="101" href="#101">101</a>     }
<a name="102" href="#102">102</a> 
<a name="103" href="#103">103</a>     @Override
<a name="104" href="#104">104</a>     <strong>public</strong> <strong>void</strong> init() throws ServletException {
<a name="105" href="#105">105</a>         <strong>super</strong>.init();
<a name="106" href="#106">106</a>         initialize();
<a name="107" href="#107">107</a>     }
<a name="108" href="#108">108</a> 
<a name="109" href="#109">109</a>     <em>/**<em>*</em></em>
<a name="110" href="#110">110</a> <em>     * Initializes the servlet, executed automatically by the servlet container&lt;br/></em>
<a name="111" href="#111">111</a> <em>     * This basically just calls the {@link #initializeEntityRequestHandler()} method and throws exceptions</em>
<a name="112" href="#112">112</a> <em>     * if something is missing</em>
<a name="113" href="#113">113</a> <em>     */</em>
<a name="114" href="#114">114</a>     <strong>protected</strong> <strong>void</strong> initialize() {
<a name="115" href="#115">115</a>         <strong>if</strong> (entityRequestHandler == <strong>null</strong>) {
<a name="116" href="#116">116</a>             <em class="comment">// call the entity request handler method</em>
<a name="117" href="#117">117</a>             entityRequestHandler = initializeEntityRequestHandler();
<a name="118" href="#118">118</a>         }
<a name="119" href="#119">119</a>         <strong>if</strong> (entityRequestHandler == <strong>null</strong>) {
<a name="120" href="#120">120</a>             <strong>throw</strong> <strong>new</strong> IllegalStateException(<span class="string">"FAILURE to get the handler during init of the direct servlet"</span>);
<a name="121" href="#121">121</a>         }
<a name="122" href="#122">122</a>     }
<a name="123" href="#123">123</a> 
<a name="124" href="#124">124</a>     <em class="comment">/*<em class="comment"> (non-Javadoc)</em></em>
<a name="125" href="#125">125</a> <em class="comment">     * @see javax.servlet.http.HttpServlet#service(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)</em>
<a name="126" href="#126">126</a> <em class="comment">     */</em>
<a name="127" href="#127">127</a>     @Override
<a name="128" href="#128">128</a>     <strong>protected</strong> <strong>void</strong> service(HttpServletRequest req, HttpServletResponse res)
<a name="129" href="#129">129</a>             throws ServletException, IOException {
<a name="130" href="#130">130</a>         <em class="comment">// we send all the incoming requests to the handler</em>
<a name="131" href="#131">131</a>         <em class="comment">// force all response encoding to UTF-8 / html by default</em>
<a name="132" href="#132">132</a>         res.setContentType(Formats.HTML_MIME_TYPE);
<a name="133" href="#133">133</a>         res.setCharacterEncoding(Formats.UTF_8);
<a name="134" href="#134">134</a>         <em class="comment">// now handle the request</em>
<a name="135" href="#135">135</a>         handleRequest(req, res);
<a name="136" href="#136">136</a>     }
<a name="137" href="#137">137</a> 
<a name="138" href="#138">138</a>     <em>/**<em>*</em></em>
<a name="139" href="#139">139</a> <em>     * Handle the incoming request (get and post handled in the same way), passes control to the</em>
<a name="140" href="#140">140</a> <em>     * dispatch method or calls the login helper, override this to control it</em>
<a name="141" href="#141">141</a> <em>     * </em>
<a name="142" href="#142">142</a> <em>     * @param req</em>
<a name="143" href="#143">143</a> <em>     *           (from the client)</em>
<a name="144" href="#144">144</a> <em>     * @param res</em>
<a name="145" href="#145">145</a> <em>     *           (back to the client)</em>
<a name="146" href="#146">146</a> <em>     * @throws ServletException</em>
<a name="147" href="#147">147</a> <em>     * @throws IOException</em>
<a name="148" href="#148">148</a> <em>     */</em>
<a name="149" href="#149">149</a>     <strong>protected</strong> <strong>void</strong> handleRequest(HttpServletRequest req, HttpServletResponse res)
<a name="150" href="#150">150</a>             throws ServletException, IOException {
<a name="151" href="#151">151</a>         <em class="comment">// catch the login helper posts</em>
<a name="152" href="#152">152</a>         String option = req.getPathInfo();
<a name="153" href="#153">153</a>         String[] parts = option.split(<span class="string">"/"</span>);
<a name="154" href="#154">154</a>         <strong>if</strong> ((parts.length == 2) &amp;&amp; ((parts[1].equals(<span class="string">"login"</span>)))) {
<a name="155" href="#155">155</a>             handleUserLogin(req, res, <strong>null</strong>);
<a name="156" href="#156">156</a>         } <strong>else</strong> {
<a name="157" href="#157">157</a>             dispatch(req, res);
<a name="158" href="#158">158</a>         }
<a name="159" href="#159">159</a>     }
<a name="160" href="#160">160</a> 
<a name="161" href="#161">161</a>     <em>/**<em>*</em></em>
<a name="162" href="#162">162</a> <em>     * handle all communication from the user not related to login</em>
<a name="163" href="#163">163</a> <em>     * </em>
<a name="164" href="#164">164</a> <em>     * @param req</em>
<a name="165" href="#165">165</a> <em>     *           (from the client)</em>
<a name="166" href="#166">166</a> <em>     * @param res</em>
<a name="167" href="#167">167</a> <em>     *           (back to the client)</em>
<a name="168" href="#168">168</a> <em>     * @throws ServletException</em>
<a name="169" href="#169">169</a> <em>     */</em>
<a name="170" href="#170">170</a>     <strong>public</strong> <strong>void</strong> dispatch(HttpServletRequest req, HttpServletResponse res) throws ServletException {
<a name="171" href="#171">171</a>         <em class="comment">// get the path info</em>
<a name="172" href="#172">172</a>         String path = req.getPathInfo();
<a name="173" href="#173">173</a>         <strong>if</strong> (path == <strong>null</strong>) {
<a name="174" href="#174">174</a>             path = <span class="string">""</span>;
<a name="175" href="#175">175</a>         }
<a name="176" href="#176">176</a> 
<a name="177" href="#177">177</a>         <em class="comment">// this cannot work because the original request data is lost</em>
<a name="178" href="#178">178</a>         <em class="comment">//      // check for the originalMethod and store it in an attribute</em>
<a name="179" href="#179">179</a>         <em class="comment">//      if (req.getParameter(ORIGINAL_METHOD) != null) {</em>
<a name="180" href="#180">180</a>         <em class="comment">//         req.setAttribute(ORIGINAL_METHOD, req.getParameter(ORIGINAL_METHOD));</em>
<a name="181" href="#181">181</a>         <em class="comment">//      }</em>
<a name="182" href="#182">182</a> 
<a name="183" href="#183">183</a>         <em class="comment">// just handle the request if possible or pass along the failure codes so it can be understood</em>
<a name="184" href="#184">184</a>         <strong>try</strong> {
<a name="185" href="#185">185</a>             <strong>try</strong> {
<a name="186" href="#186">186</a>                 entityRequestHandler.handleEntityAccess(req, res, path);
<a name="187" href="#187">187</a>             } <strong>catch</strong> (EntityException e) {
<a name="188" href="#188">188</a>                 log.warn(<span class="string">"Could not process entity: "</span>+e.entityReference+<span class="string">" ("</span>+e.responseCode+<span class="string">")["</span>+e.getCause()+<span class="string">"]: "</span>+e.getMessage());
<a name="189" href="#189">189</a>                 <em class="comment">// no longer catching FORBIDDEN or UNAUTHORIZED here</em>
<a name="190" href="#190">190</a>                 <em class="comment">//            if (e.responseCode == HttpServletResponse.SC_UNAUTHORIZED ||</em>
<a name="191" href="#191">191</a>                 <em class="comment">//                  e.responseCode == HttpServletResponse.SC_FORBIDDEN) {</em>
<a name="192" href="#192">192</a>                 <em class="comment">//               throw new SecurityException(e.getMessage(), e);</em>
<a name="193" href="#193">193</a>                 <em class="comment">//            }</em>
<a name="194" href="#194">194</a>                 sendError(res, e.responseCode, e.getMessage());
<a name="195" href="#195">195</a>             }
<a name="196" href="#196">196</a>         } <strong>catch</strong> (SecurityException e) {
<a name="197" href="#197">197</a>             <em class="comment">// the end user does not have permission - offer a login if there is no user id yet</em>
<a name="198" href="#198">198</a>             <em class="comment">// established,  if not permitted, and the user is the anon user, let them login</em>
<a name="199" href="#199">199</a>             <strong>if</strong> (getCurrentLoggedInUserId() == <strong>null</strong>) {
<a name="200" href="#200">200</a>                 log.debug(<span class="string">"Attempted to access an entity URL path ("</span> + path
<a name="201" href="#201">201</a>                         + <span class="string">") for a resource which requires authentication without a session"</span>, e);
<a name="202" href="#202">202</a>                 <em class="comment">//            // store the original request type and query string, this is needed because the method gets lost when Sakai handles the login</em>
<a name="203" href="#203">203</a>                 <em class="comment">//            path = path + (req.getQueryString() == null ? "?" : "?"+req.getQueryString()) + ORIGINAL_METHOD + "=" + req.getMethod();</em>
<a name="204" href="#204">204</a>                 path = path + (req.getQueryString() == <strong>null</strong> ? <span class="string">""</span> : <span class="string">"?"</span>+req.getQueryString()); <em class="comment">// preserve the query string</em>
<a name="205" href="#205">205</a>                 handleUserLogin(req, res, path);
<a name="206" href="#206">206</a>                 <strong>return</strong>;
<a name="207" href="#207">207</a>             }
<a name="208" href="#208">208</a>             <em class="comment">// otherwise reject the request</em>
<a name="209" href="#209">209</a>             String msg = <span class="string">"Security exception accessing entity URL: "</span> + path + <span class="string">" (current user not allowed): "</span> + e.getMessage();
<a name="210" href="#210">210</a>             log.warn(msg);
<a name="211" href="#211">211</a>             sendError(res, HttpServletResponse.SC_FORBIDDEN, msg);
<a name="212" href="#212">212</a>         } <strong>catch</strong> (Exception e) {
<a name="213" href="#213">213</a>             <em class="comment">// all other cases</em>
<a name="214" href="#214">214</a>             String msg = entityRequestHandler.handleEntityError(req, e);
<a name="215" href="#215">215</a>             log.warn(msg, e);
<a name="216" href="#216">216</a>             sendError(res, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, msg);
<a name="217" href="#217">217</a>         }
<a name="218" href="#218">218</a> 
<a name="219" href="#219">219</a>     }
<a name="220" href="#220">220</a> 
<a name="221" href="#221">221</a>     <em>/**<em>*</em></em>
<a name="222" href="#222">222</a> <em>     * handles sending back servlet errors to the client,</em>
<a name="223" href="#223">223</a> <em>     * feel free to override this if you like to handle errors in a particular way</em>
<a name="224" href="#224">224</a> <em>     * </em>
<a name="225" href="#225">225</a> <em>     * @param res the http servlet response (back to the client)</em>
<a name="226" href="#226">226</a> <em>     * @param code servlet error response code</em>
<a name="227" href="#227">227</a> <em>     * @param message extra info about the error</em>
<a name="228" href="#228">228</a> <em>     */</em>
<a name="229" href="#229">229</a>     <strong>protected</strong> <strong>void</strong> sendError(HttpServletResponse res, <strong>int</strong> code, String message) {
<a name="230" href="#230">230</a>         <strong>try</strong> {
<a name="231" href="#231">231</a>             res.reset();
<a name="232" href="#232">232</a>             res.sendError(code, message);
<a name="233" href="#233">233</a>         } <strong>catch</strong> (Exception e) {
<a name="234" href="#234">234</a>             log.warn(<span class="string">"Error sending http servlet error code ("</span>+code+<span class="string">") and message ("</span>+message+<span class="string">"): "</span> + e.getMessage(), e);
<a name="235" href="#235">235</a>         }
<a name="236" href="#236">236</a>     }
<a name="237" href="#237">237</a> 
<a name="238" href="#238">238</a> }
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